Methods and hollow profiles of the kind mentioned at the outset are already known from the prior art. Patent application DE 10 2005 044 172 A1, for example, describes an arrangement consisting of a plurality of moulded parts between which a reinforcement element is positioned, wherein the moulded parts and the reinforcement element are welded at flanges which project outwards and are provided on all components. The reinforcement element essentially provides the profile, which is formed from the moulded parts, with improved dimensional stability. However, the disadvantage of the procedure described in DE 10 2005 044 172 A1 is that all of the joints between the moulded parts which are to be joined and the reinforcement element are joined at points which lie outside the boundaries defining the interior of the profile. The flanges projecting outwards increase the space requirement of the individual components of the profile and of the profile itself. As a result, in particular the manageability of the hollow profiles, for example when storing but also when being processed, is affected. Moreover, the profile flanges are only suitable in a limited way for joining the profile to other components or, where appropriate, to other profiles.
This is because a joint at the flanges which has already been produced can be affected by subsequent joining processes to be performed at the flanges. This difficulty could be avoided by carrying out the joining processes that are used to manufacture the profile and are performed at the flanges and the joining processes that are used to join the profile to another component and are performed at the flanges, at the same time, essentially in the same work step. However, this would considerably restrict the flexibility of use of the profile. Alternatively, it is possible to provide flanges with a specific minimum width that provides a spatial separation between two joining processes, which to a large extent are independent from one another, that are performed at these flanges. However, the space requirement would be additionally increased by this action.
Furthermore, it has come to light that the welding of sheets performed at flanges can lead to a non-uniform welding result if the flanges have thicknesses that differ from one another. In order to avoid this effect, according to the prior art the thicker flanges can be reduced to approximately the thickness of the thinnest flange. For this purpose, milling, grinding or stamping techniques are applied. An example of a stamping technique is disclosed in patent application DE 10 2004 040 569 A1. However, the number of work steps in advance of the actual method for manufacturing a profile is increased by this procedure. In addition, the material of the sheets is already exposed to additional stress in the form of deformation before the actual manufacturing process.